JPH0579960U - Photovoltaic element - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] An improved cell of a photovoltaic element that is small in size and capable of obtaining a high output current by increasing the effective area of the photovoltaic element formed on a substrate. shape. [Structure] A pair of terminal electrode layers 60 and 70 are formed on a substrate 10, and a plurality of translucent electrodes 20 and 2 are formed on other portions.
0, and back electrodes 40, 40, which face the translucent electrode, are formed, and the semiconductor electromotive force layer 30 is formed between them.
It is formed by connecting a plurality of cells in series. As for the shape of the cell formed by the translucent electrode 20 and the back electrode 40, at least both ends thereof are formed in a trapezoidal shape, and the effective areas of the cells formed on the substrate are made substantially equal. With such an electrode structure, it is possible to maximize the effective area of the formed cell and obtain a small and high output current.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a photovoltaic device using an amorphous semiconductor layer such as an amorphous silicon solar cell, and more particularly to improvement of the electrode shape thereof.

[0002]

[Prior Art]

 An example of a general configuration of a photovoltaic element using an amorphous semiconductor layer such as an amorphous silicon solar cell will be described with reference to the drawings. In such a conventional photovoltaic element, as shown in FIG. 4, first, a thin layer of indium oxide or tin oxide is formed on a transparent substrate 1 such as a glass substrate or a transparent flexible film. The transparent electrodes 2, 2, ... Are formed. At the same time, terminal electrodes 6 and 7 made of thin layers of indium oxide or tin oxide are also formed on both ends of one side of the transparent substrate 1 (both ends of the upper side of the figure).

Next, as shown in FIG. 5, an amorphous semiconductor layer 3 including a P-type layer, an I-type layer, and an N-type layer is formed on this upper surface. Further, as shown in FIG. 6, metallic rear electrodes 4, 4, ... Are formed on the transparent electrode 2, 3 ... In a position and shape corresponding to the transparent electrodes 2, 2 ,. At this time, a part of these back electrodes 4, 4, ... Is extended on the connecting electrode portions 21, 21, ... Formed so as to project from a part of the transparent electrodes 2, 2 ,. The connection electrode portions 41, 41 formed in this manner are overlapped with each other to establish electrical connection between them.

That is, in an amorphous silicon solar cell, usually, the transparent electrodes 2, 2 ... And the back electrodes 4, 4, ... Are formed in a plurality of sets on a single transparent substrate 1. A plurality of cells, which are electromotive units, are formed by including the semiconductor electromotive force layer 3 inserted between them. Then, the plurality of cells are connected in series via the connection electrode portions 21, 21, ..., 41 1, 41, ... As a result, a plurality of sets of solar cells are connected in series. That is, the electric power collected by the electrodes of each of these cells is output from the terminal electrodes 6 and 7 provided at both ends of the transparent substrate 1, so that a large voltage can be taken out.

After that, as shown in FIG. 6, the transparent electrodes 2, 2 ..., the back electrodes 4, 4, ... Formed on the translucent substrate 1, and the connection electrode portions 21, 21 ,. 41 is covered with a protective layer 5 such as an epoxy resin for protection.

By the way, in the photovoltaic device having the above structure, the current that can be extracted from each device is the smallest cell among the cells formed by partitioning the translucent substrate. Limited by area. Further, the terminal electrodes 6 and 7 formed on the translucent substrate also require a certain area for practical use. Therefore, as shown in FIG. 4, in the conventional amorphous silicon solar cell, in order to secure the area of these electrodes, the area of the cells at the left and right ends on the translucent substrate 1 is large, and the area of the cell in between is large. A structure was used to reduce the.

[0007]

[Problems to be solved by the device]

 That is, in the above conventional technique, the shape of each element forming the amorphous silicon solar cell, that is, the shape of each cell formed on the transparent substrate 1 is a rectangle or a square. As a result, in the structure where the area of the cells on both the left and right ends is increased to secure the area of the terminal electrode and the size of the intermediate cell is reduced, the output current value is restricted by the area of the intermediate cell, and the cell with large area on both ends is Includes the area that does not contribute to the output.

In view of the above-mentioned problems in the prior art, the present invention proposes a structure of a photovoltaic element that maximizes the effective area of the photovoltaic element, is small, and can obtain a high output current. The purpose is to do.

[0009]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention forms a pair of terminal electrode layers on a substrate and forms a plurality of translucent electrode layers and an equal number of back electrode layers facing the translucent electrode layers. A semiconductor electromotive force layer is formed between the translucent electrode layer and the back electrode layer, which are arranged to face each other, and the translucent electrode layer, the back electrode layer and the semiconductor electromotive force are formed. In a photovoltaic element formed by connecting a plurality of cells composed of layers in series, the shape of the transparent electrode layer and the back electrode layer which form at least one cell of the plurality of cells is set to a base. Provided is a photovoltaic element having a shape, in which effective areas of cells formed on the substrate are made substantially equal.

[0010]

[Action]

 According to the structure of the photovoltaic element according to the above-mentioned invention, the transparent electrode and the back electrode which are arranged to face each other on one substrate, and the plurality of semiconductor electromotive force layers sandwiched by these electrodes are formed. Even if the terminal electrodes having a sufficient area are formed at both ends of the substrate by replacing at least a part of the shape of the cell with a rectangular shape or a square, which is a conventional cell shape, with a shape including a trapezoid, It is possible to make the area of the cells at both ends almost the same as the area of the middle cell, eliminating the unnecessary area of the cell and obtaining higher output efficiency. Therefore, higher output with the same cell size The electric current is obtained.

[0011]

【Example】

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 and 2 show the internal structure of a photovoltaic device according to an embodiment of the present invention in detail along with its manufacturing process. That is, in FIG. 2, as in the above-mentioned conventional technique, a transparent electrode layer 20, which is a thin layer of indium oxide or tin oxide, is formed on a transparent substrate 10 such as a glass substrate or a transparent flexible film. Form 20 ... More specifically, in this example, SnO ₂ was deposited as a TCO film on a silica-coated glass substrate serving as the translucent substrate 10 by the CMD method so as to have a thickness of 800 × 10 ⁻¹⁰ m (angstrom). It was After that, a predetermined pattern shown in the drawing was formed by a wet etching method. At this time, as is apparent from the figure, a pair of terminal electrodes 60 and 70 are formed and formed at both ends of one side of the transparent substrate 10 (both ends of the upper side of the figure). A part of the transparent electrodes 20, 20 ... Is extended to form connection electrode portions 22, 22.

Subsequently, on the upper surface of the transparent electrodes 20, 20 ... Formed as described above, specifically, on the portion shown by the alternate long and short dash line in FIG. An amorphous semiconductor layer 30 which is a power layer was formed. In this embodiment, first, B-doped amorphous silicon is formed to a film thickness of 200 × 10 ⁻¹⁰ m, then undoped amorphous silicon is formed to a film thickness of 400 × 10 ⁻¹⁰ m, and finally, A P-doped amorphous silicon film having a film thickness of 200 × 10 ⁻¹⁰ m was formed in a predetermined pattern by a plasma CVD method using a metal mask method.

Thereafter, as shown in FIG. 1, metallic back electrode layers 40, 40 ... Are formed on the transparent electrodes 20, 20 ... In a position and shape corresponding to the transparent electrodes 20, 20. In this example, Al was formed into a film having a film thickness of 1500 × 10 ⁻¹⁰ m in a predetermined pattern by a vacuum evaporation method using a metal mask method. At this time, a part of the back electrodes 40, 40 ... Is extended on the connection electrode portions 22, 22 ... Formed by projecting from a part (the upper part of the figure) of the transparent electrodes 20, 20. The connection electrode portions 42, 42 formed as above are overlapped with each other and electrical connection between them is performed as in the above-described conventional technique.

Further, after that, the transparent electrodes 20, 20, ..., The back electrodes 40, 40 ... Formed on the translucent substrate 10, and the connection electrode portions 22, 22 ,. A part, that is, a part surrounded by a chain double-dashed line in the drawing is covered with a protective layer 50 made of, for example, an epoxy resin for protection. In this example, the resin was printed and fired, scribed with a glass scriber, and further broken to complete each solar cell.

In the photovoltaic device according to the embodiment of the present invention, that is, in the amorphous silicon solar cell completed as described above, the transparent electrodes 20, 20 ... Back electrodes 40, 40 ... A plurality of cells, which are electromotive force units, are formed by including a semiconductor electromotive force layer 30 which is formed on one translucent substrate 10 by being divided into a plurality of sets and inserted between them. The plurality of cells are connected in series via the connection electrode parts 22, 22, ..., 42 2, 42 .. As a result, a plurality of sets of solar cells are connected in series. This is also the same as the above-mentioned conventional technique. The electric power collected by the electrodes of each cell is output from the terminal electrodes 60 and 70 provided at both ends of the translucent substrate 10 so that a large voltage can be taken out. It is the same.

By the way, according to the present invention, as is apparent from FIGS. 1 and 2, the shape of a plurality of cells formed on the surface of one translucent substrate 10 is characteristic. That is, according to the present invention, in order to make the effective areas of the cells substantially equal to each other, the shape of the cells to be formed is replaced by the conventional rectangle or square, and at least a part thereof includes a trapezoid. More specifically, in the embodiments shown in FIGS. 1 and 2, the shapes of the cells at the left end and the left end in the figure where the upper side is long are trapezoidal (however, the cell at the right end is The shape of the cell has a smaller degree of trapezoidal deformation than the cell shape at the left end.) Along with that, the shape of the intermediate cell is also deformed, and as a whole, the area of each cell is almost equal. Is set to. This eliminates the unnecessary area increase of cells at both ends, which was difficult to avoid by the conventional structure, and enables higher output efficiency to be obtained. That is, a higher output current can be obtained even with the same cell size.

In order to verify this, the solar cells manufactured by the above-mentioned examples were irradiated with a white fluorescent lamp 200 (lux), and the results of measuring the operating current with respect to a predetermined operating voltage are shown in the table below. 1 is shown. In this table, the sizes of Example 1 and Example 2 are different (for example, a large-sized solar cell having 11 cells formed on a substrate as shown in FIG. 3). In the conventional example 1 and the conventional example 2 for, as shown in FIGS. 4 to 7, each cell has a rectangular shape.

[0018]

[Table 1] ─────────────────────────────────── Size Both ends Cell surface Intermediate number of cells Effective effect Operation Horizontal x Vertical (left / right) Area utilization factor Current value Voltage value (m) (mm ² ) (mm ² ) (ke) (%) (μA) (μV) ──────── ──────────────────────────── Example 1 15 × 10 14.3 14.3 5 100 2.50 2.0 Conventional example 1 15 × 10 26 / 19.5 8.6 5 60.6 1.50 2.0 Example 2 35 × 13.5 25.5 25.5 11 100 4.40 2.0 Conventional example 2 35 × 13.5 40/30 23.3 11 91.37 4.00 2.0 ──────────────────── ──────────────
─

As is clear from this comparison result, it is understood that the electrode structure (shape) of the present invention can significantly improve the operating current value as compared with the conventional example.

Further, as another embodiment of the present invention, although not shown, a solar cell of a type different from that of the above embodiment was prepared, and the same output test was performed. The results are shown in Table 2 below. 3 shows. In addition, other Examples 3 and 4 are flexible types, in which a SiO ₂ coat having a film thickness of 20 μm is formed on a 200 μm stainless steel substrate by a spray method, and Cr is 800 × 10 ⁻¹⁰ on the SiO ₂ coat. A film having a thickness of m was formed in a predetermined pattern using a metal mask method by a sputtering method. Then, by PCVD method, P-doped amorphous silicon is formed to a film thickness of 200 × 10 ⁻¹⁰ m, I-doped amorphous silicon is formed to a film thickness of 4000 × 10 ⁻¹⁰ m, and B-doped amorphous silicon is formed to a film thickness of 200 × 10 ⁻¹⁰ m. A film having a thickness of × 10 ^-10 m was formed into a predetermined pattern by using a metal mask method. After that, ITO was formed into a film with a film thickness of 800 × 10 ⁻¹⁰ m by using a metal mask method, and a transparent resin was attached to the surface by a printing and baking method to obtain a solar cell.

[0021]

[Table 2] ─────────────────────────────────── Size Both ends Cell surface Intermediate number of cells Effective effect Operation Horizontal x Vertical (left / right) Area utilization factor Current value Voltage value (m) (mm ² ) (mm ² ) (ke) (%) (μA)
(μV) ──────────────────────────────────
─ Example 3 15 × 10 14.3 14.3 5 100 1.90 2.0 Conventional Example 3 15 × 10 26 / 19.5 8.6 5 60.6 1.15 2.0 Example 4 15 × 10 25.5 25.5 11 100 3.40 2.0 Conventional Example 4 35 × 13.5 40/30 23.3 11 91.37 3.00 2.0 ───────────────────────────────────
─

Further, Examples 5 and 6 are see-through type, and Al of the back electrode is formed into a transparent film having a film thickness of 800 × 10 ⁻¹⁰ m in the same manner as Example 1 of FIGS. 1 and 2 above. Instead of ITO, which has optical properties, a resin as a protective layer on the back surface is also made transparent.

[0023]

[Table 3] ─────────────────────────────────── Size Both-end cell surface Intermediate cell number Effective Operation Horizontal x Vertical (left / right) Area utilization factor Current value Voltage value (m) (mm ² ) (mm ² ) (ke) (%) (μA)
(μV) ──────────────────────────────────
─ Example 5 15 × 10 14.3 14.3 5 100 2.10 2.0 Conventional Example 5 15 × 10 26 / 19.5 8.6 5 60.6 1.25 2.0 Example 6 35 × 13.5 25.5 25.5 11 100 3.60 2.0 Conventional Example 6 35 × 13.5 40/30 23.3 11 91.37 3.30 2.0 ──────────────────────────────────
─

Also in these other Examples 3 to 6, the shape of the cells formed at both ends thereof is trapezoidal as in the above, and the area of the cells at both ends and the area of the intermediate cell are made substantially the same. Needless to say Then, as is clear from the actual measurement results shown in Tables 2 and 3, the operating current value can be significantly improved.

[0025]

[Effect of the device]

 As is clear from the above detailed description, the photovoltaic device according to the present invention maximizes the effective area of a cell formed on one substrate, and achieves a small size and high output current. It has the excellent effect that it becomes possible.

[Brief description of drawings]

FIG. 1 is a plan view showing an electrode structure of a photovoltaic device according to an embodiment of the present invention.

FIG. 2 is a plan view showing an electrode structure of the photovoltaic device of the present invention, similar to FIG.

FIG. 3 is a plan view showing a modified example of the photovoltaic device of the present invention.

FIG. 4 is a plan view showing an electrode structure of a photovoltaic device according to a conventional technique.

FIG. 5 is a plan view showing the electrode structure of the conventional photovoltaic device together with FIG.

6 is a plan view showing an electrode structure of the conventional photovoltaic device together with FIG. 4 described above.

FIG. 7 is a plan view showing an electrode structure of the photovoltaic device of the related art, similar to the above.

[Explanation of symbols]

 10 translucent substrate 20 transparent electrode layer 30 amorphous semiconductor layer 40 back electrode layer 60, 70 terminal electrode

Claims (1)

[Scope of utility model registration request] 1. A pair of terminal electrode layers are formed on a substrate, a plurality of translucent electrode layers and the same number of back electrode layers facing the translucent electrode layers are formed, and these are arranged to face each other. A semiconductor electromotive force layer is formed between the translucent electrode layer and the back electrode layer, and a plurality of cells composed of the translucent electrode layer, the back electrode layer and the semiconductor electromotive force layer are formed. In a photovoltaic element connected in series, the translucent electrode layer and the back electrode layer forming at least one cell of the plurality of cells are trapezoidal and formed on the substrate. Photovoltaic device characterized in that the effective area of each cell is substantially equal.